1. Field of the Invention
The present invention relates to a rotor for laboratory centrifuges wherein said rotor comprises a rotor housing that is open to the top and has at least one recess for taking up centrifuge containers, wherein the recess is formed in the peripheral area of the rotor as a concentric circumferential ring trough with an inner wall and an outer wall and also an adapter for taking up a sample container and for use in such a laboratory centrifuge rotor.
2. Description of the Related Art
In this context, a centrifuge container can firstly be a sample container in which the samples to be centrifuged are arranged. Secondly, a centrifuge container can also be an adapter that can be inserted into a rotor and into which a sample container can in turn be inserted.
A rotor for a laboratory centrifuge is used in order to take up centrifuge containers in which material to be centrifuged is contained. A centrifuge container, such as, for example, a test tube, can be placed in a cylindrical recess, a plurality of which is provided in a rotor, as disclosed in the patent application U.S. Pat. No. 5,411,465.
An angular cap for centrifuges is described in the patent application DE 37 03 514 A1, wherein said angular cap has a recess for taking up sample material. The recess is designed in the peripheral area of the rotor as a concentric circumferential annular groove that is bordered on its edge seen in the direction of the rotor axis by an axially symmetrical, upwardly tapering truncated cone. The outer wall of the annular groove is designed in the form of an upwardly tapering hollow truncated cone. Centrifuge containers are arranged in a row in the recess of the rotor. The design of the recess as a annular groove reduces the weight of the rotor which in turn acts advantageously on the centrifugation properties of the rotor; thus for example in case of a constant rotational speed, the centripetal force acting on the rotor is reduced. On the other hand, the circumferential recess reduces the stability of the rotor since the smaller mass and the design as a hollow truncated cone reduces the resistance of the rotor peripheral area compared to the centrifugal force. Thus this can result in breakage on the rotor housing and damages, especially in the lower peripheral area of the annular groove wherein said peripheral area protrudes over the rotor hub. Also, due to the design as an annular groove, for example, an uneven filling of the centrifuge containers or an uneven loading of the centrifuge can amount to an ovalization of the rotor body during the centrifugation process. This causes unbalances and brings about an unsafe centrifugation.
Furthermore, the required high production accuracy in this construction involves the risk of the occurrences of inaccuracies in the fit of the centrifuge containers in the annular groove, which in turn can result in constantly changing unbalances and resonance vibrations in case of certain number of revolutions.